linux-kernel - Re: [PATCH] devcoredump: increase the device delete timeout to 10 mins

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Date:   Tue, 08 Feb 2022 21:35:11 +0100
From:   Johannes Berg <johannes@...solutions.net>
To:     Abhinav Kumar <quic_abhinavk@...cinc.com>,
        linux-kernel@...r.kernel.org
Cc:     gregkh@...uxfoundation.org, rafael@...nel.org, robdclark@...il.com,
        dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, seanpaul@...omium.org,
        swboyd@...omium.org, nganji@...eaurora.org,
        aravindh@...eaurora.org, khsieh@...eaurora.org, daniel@...ll.ch,
        dmitry.baryshkov@...aro.org
Subject: Re: [PATCH] devcoredump: increase the device delete timeout to 10
 mins

On Tue, 2022-02-08 at 11:44 -0800, Abhinav Kumar wrote:
> There are cases where depending on the size of the devcoredump and the speed
> at which the usermode reads the dump, it can take longer than the current 5 mins
> timeout.
> 
> This can lead to incomplete dumps as the device is deleted once the timeout expires.
> 
> One example is below where it took 6 mins for the devcoredump to be completely read.
> 
> 04:22:24.668 23916 23994 I HWDeviceDRM::DumpDebugData: Opening /sys/class/devcoredump/devcd6/data
> 04:28:35.377 23916 23994 W HWDeviceDRM::DumpDebugData: Freeing devcoredump node
> 
> Increase the timeout to 10 mins to accommodate system delays and large coredump
> sizes.
> 

No real objection, I guess, but can the data actually disappear *while*
the sysfs file is open?!

Or did it take 5 minutes to open the file?

If the former, maybe we should fix that too (or instead)?

johannes